The embodiments herein relate generally to treatment fluids for stimulation of subterranean formations and, more particularly, to treatment fluids comprising a pseudo-crosslinking agent and an acidic viscoelastic surfactant base fluid for stimulation of subterranean formations.
Treatment fluids may be used in a variety of subterranean treatment operations. Such treatment operations may include, without limitation, drilling operations, stimulation operations, production operations, remediation operations, sand control treatments, and the like. The term “treatment fluid,” and grammatical variants thereof, refers to any fluid that may be used in a subterranean treatment operation (also referred to simply as “treatment” or “operation” herein) in conjunction with a desired function and/or for a desired purpose. The term “treatment fluid” does not imply any particular action by the fluid or any component thereof.
Well stimulation may be performed on a subterranean formation to achieve, increase, or restore fluid production therefrom, such as hydrocarbons including oil and gas. For example, a well that exhibits low permeability can be stimulated to instigate production from a formation. Further, well stimulation can be used to restore near-wellbore permeability and enhance flow from an already existing formation that has become under-productive or even unproductive. In some instances, the well stimulation operation is an acidizing operation, which may include matrix acidizing or fracture acidizing.
During a matrix acidizing operation, an acid-soluble material in a subterranean formation is dissolved by one or more acids to expand flow pathways in the subterranean formation, to create new flow pathways in the subterranean formation, to remove acid-soluble precipitation damage in the subterranean formation, and/or to increase flow to/from the matrix. The one or more acids are introduced at a pressure below the fracture pressure of the formation, but often at high rate. As used herein, the term “fracture pressure,” and grammatical variants thereof, refers to the pressure above which injection of fluids will cause a formation to fracture hydraulically. Accordingly, during a matrix acidizing operation, the acid can penetrate the formation and extend the depth of the treatment without fracturing the formation.
Fracture acidizing, on the other hand, seeks to fracture the formation during the acidizing treatment. Accordingly, during a fracture acidizing operation, one or more acids are introduced into a subterranean formation at a pressure above the fracture pressure, and often at high rate, to dissolve acid-soluble materials therein. The introduced one or more acids thus may create or enhance fractures in the formation, while simultaneously etching channels in the fracture faces (i.e., the surface of the fractures) for enhancing fluid conductivity therethrough. The etching may form a nonuniform pattern that can permit fluid flow through the channels and the fractures to a surface location without propping open the fractures.